package leetcode;

/**
 * Created with IntelliJ IDEA.
 * Description:21. 合并两个有序链表
 * User: 东莞呵呵
 * Date:2022-07-10
 * Time:10:12
 */
public class TestDemo2 {
    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        if(list1==null&&list2==null){
            return list1;
        }else if(list1==null){
            return list2;
        }else if (list2==null){
            return list1;
        }
        ListNode head=null;
        if(list1.val<list2.val){
            head=list1;
            list1=list1.next;
        }else{
            head=list2;
            list2=list2.next;
        }
        ListNode cur=head;
        while(list1!=null&&list2!=null){
            if(list1.val<list2.val){
                cur.next=list1;
                list1=list1.next;
            }else{
                cur.next=list2;
                list2=list2.next;
            }
            cur=cur.next;
        }
        cur.next=list1!=null?list1:list2;
        return head;
    }
}
